利用所测容器中水和蒸汽的导电率差异的特性进行测量，由于液位的变化使部分电极浸入水中，部分电极置于蒸汽中，浸入炉水中的电极对筒体阻抗减小，而置于蒸汽中的电极对筒体的阻抗增大。利用这一特性，可将非电量的水位转化为电量，送给智能二次仪表，从而实现水位的显示、报警、保护、联锁之功能。

For the convenience of piping engineers, the following pages show the allowable pressure rating at temperature of various piping materials including Stainless Steel Type 304 and 316 in sizes ½” through 24” in popular wall schedules. Stress values shown at various temperatures are as given in Appendix A of ANSI B31.3-Code for Pressure Piping for Petroleum Refinery Piping. The allowable pressure ratings have been calculated from the basic formula given in ANSI B31.3 as

功 能 ： 联锁控制/报警输出/回路通断状态检测/就地故障显示/可根据客户要求设计